In motorcycle races especially when the going is muddy or dusty the conventional goggles, or transparent face mask on the mandatory helmet quickly become obscured so that they must be repeatedly cleaned or there is a strong temptation for the motorcyclist to remove the goggles or face mask permanently thus risking eye damage.
One solution sometimes used is to provide multiple layers of transparent plastic such as acetate, over the lenses of the goggles, so that individual and successive layers can be stripped off to uncover clean surfaces.
Liquid curtain shower pipes have been incorporated into the upper frame of goggles to clean the lenses when a bulb is pressed as in U.S. Pat. No. 1,354,433 to DeFelice of Sept. 28, 1920.
A similar set of goggles with attached washing means is disclosed in U.S. Pat. No. 2,971,196 to Howell of Feb. 14, 1961 wherein pressure is obtained from an air bladder mounted on the back of a rider and controlled by a valve held in the hand.
One disadvantage of a helmet-carried tank, or a back carried liquid supply, is that it adds unduly to the weight carried by the rider, thus being especially inconvenient in the slippery muddy environment and high speed travel encountered by a motorcycle racer.